or is a primitive that is used to check if either of two conditions is true. Given two checks to make (true-or-false statements), or will report true if 1) the first is true, 2) the second is true, 3) both are true and will only report false if both of the conditions are false. As a concrete example, say you had a pig and you wanted it to eat the food on its patch whether it was animal food or human food, you could model that in code using if animal-food-here or people-food-here [eat]. Additionally, if you wanted to check more than just two conditions, you can just string together a series of of statements like so: if A or B or C or D [ do-something].

In this model, or is used to check if a soccer ball is within or outside of the net. Using the check-if-miss procedure, if the ball is outside of the boundaries of the net, we color it red, and if it is inside, we color it green. In the code, we check if the ball is too far to the right or too far to the left or too high. (In this model, the center of the world is set to be the center of the bottom edge to make the math easier.)

PS. Note that under the hood, in practice NetLogo often only has to check the first of the two conditions to see if the or will report true or not. Imagine we are checking two conditions, condition1 and condition2. If we write if condition1 or condition2 and condition1 is true, regardless of whether condition2 is true or false, the or will always report true, so why bother checking condition2. This is called "short-circuit or" and you will see it in most modern programming languages because it allows for faster code execution as well as some other benefits to advanced programmers. The takeaway for beginner programmers, however, is simpler: if you need to use or to combine two checks, place the less computationally expensive check first, because if it reports true, then you never have to waste the computer's time checking the expensive one.